The glucose level of plasma, serum, urine and other bodily fluids is conveniently determined by oxidation catalyzed by glucose oxidase employing a polarographic oxygen sensor with a circuit modified to measure the rate of oxygen consumption. Data obtained from a population of 789 urine samples collected from normal subjects of both sexes and all ages are presented. From the data, it appears that the renal threshold for glucose is dependent upon the threshold of the analytic method employed. Urinary interferences associated with prior glucose oxidase methods are circumvented by measuring oxygen consumption instead of peroxide formation.